The present invention generally relates to an automatic safe disposable blood sampling device for medical use, more particularly, to a casing self-locking type of automatic safe blood sampling device, in which a press button of which is locked by engagement thereof with the casing of the blood sampling device after a lancet needle of the blood sampling device is launched so that the blood sample device is brought into a self-locking state and can not be reused.
Various types of medical blood sampling device are known, there is a tendency to develop a “mini” type automatic blood sampling device which is safe and disposable once the lancet needle is launched. In order to make it disposable, this kind of blood sampling device is provided with a disposable self-locking mechanism which achieves self-locking effect immediately after a lancet needle of the blood sampling device is launched, thus causing the catch-launching mechanism failure. Therefore, the potential safety hazards involved in the previous blood sampling device are thoroughly eliminated.
Presently, there are two types of self-locking mechanism. The first type of self-locking mechanism employs a structure in which the lancet needle is engaged with a casing, that is, the lancet needle and the casing each are provided with a special structure, the engagement of the lancet needle with the casing achieves a self-locking effect after the lancet needle of the blood sampling device is launched. For example, the Chinese Utility Model No. CN2486104Y filed on Jul. 30, 2001 and granted to the applicant of the present application on Apr. 17, 2002 discloses an automatic safe disposable blood sampling device having a new type catch-launching mechanism, in the blood sampling device of the above Chinese Utility Model No. CN2486104Y, an elastic arm C is slantwise provided on the lancet needle and a stopping notch is provided in the casing of the blood sampling device. After the lancet needle of blood sampling device is launched, the elastic arm C is retracted together with the lancet needle so as to fall into the stopping notch to be self-locked therewith.
The second type of self-locking mechanism is a lancet needle self-locking structure, that is, the self-locking mechanism is completely provided on the lancet needle, and achieves a self-locking effect after the lancet needle of the blood sampling device is launched. For example, the Chinese Patent Application No. 200420025752.5 filed on Mar. 25, 2004 by the same applicant as that of the present application discloses an automatic safe disposable blood sampling device of lancet needle self-locking type. In the blood sampling device, and an elastic arm is provided on a side portion of the lancet needle. A self-locking hook is provided on an end of the elastic arm, and the elastic arm is inwardly bent upon application of an external force when the lancet needle of the blood sampling device is launched by pressing. Consequently, and the end is forced across the hook so as to be caught by the self-locking hook, thus achieving the self-locking effect. The above two types of self-locking mechanisms have disadvantageous in their structures, features and effects respectively.